Thyroid Symptom Assessment: Three clinical symptom scales (Hyperthyroid Symptom Scale,60 Modified Billewicz Index for Hypothyroidism,61, 62 and the Hypothyroid Symptom Scale) will be used to assess and document potential thyroid-related symptoms. See attachment B for details. The hypothyroid scale is a patient self-assessment and will be completed by the patient at the beginning of the visit. The hyperthyroid scale and modified Billewicz will be completed by the Investigator or designee. The same scales are currently in use in the ongoing DITPA studies.